Tanaka 1897 Shotgun Problem

I have decided to sell my Tanaka 1897, so as I'd never fired it before I thought I should make sure it's in working order, I charged the 2 shells that comes with it then loaded them in to the magazine I then pumped the action to load the first shell, it loaded ok the problem was that as I snapped the action shut the second shell ejected itself from the magazine, I fiddled with it for while but the problem persisted, so can anyone help as I'd like to get it sold but it needs to be in working order.